Field of the Invention
The invention relates to bi-directional shift registers, and more particularly to bi-directional shift registers capable of reducing the falling time of an output pulse and reducing the power consumption.
Description of the Related Art
Shift registers have been widely used in data driving circuits and gate driving circuits used in display devices to control timing when receiving a data signal in each data line, as well as to generate a scanning signal for each gate line. In a data driving circuit, the shift register outputs a selection signal to each data line, so as to write the image data into each data line. In a gate driving circuit, the shift register outputs a scanning signal to each gate line, so as to write the image signal provided to each data line in the pixels of a pixel array.
A conventional shift register generates the selection signal or scanning signal in only a single direction. However, a single scanning direction does not satisfy the entire requirements of LCD products. For example, some displays of digital cameras are rotated according to the placement angle of the camera. In addition, some LCD monitors comprise the function of rotating the monitor. Therefore, novel bi-directional shift registers capable of outputting signals in a forward direction and a reverse direction, and further reducing the falling time of an output pulse and reducing the power consumption, are highly desired.